hardware/arduino/sam/system/CMSIS/CMSIS/DSP_Lib/Source/ComplexMathFunctions/arm_cmplx_dot_prod_f32.c

/* ----------------------------------------------------------------------   
* Copyright (C) 2010 ARM Limited. All rights reserved.   
*   
* $Date:        15. July 2011  
* $Revision: 	V1.0.10  
*   
* Project: 	    CMSIS DSP Library   
* Title:		arm_cmplx_dot_prod_f32.c   
*   
* Description:	Floating-point complex dot product   
*   
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*  
* Version 1.0.10 2011/7/15 
*    Big Endian support added and Merged M0 and M3/M4 Source code.  
*   
* Version 1.0.3 2010/11/29  
*    Re-organized the CMSIS folders and updated documentation.   
*    
* Version 1.0.2 2010/11/11   
*    Documentation updated.    
*   
* Version 1.0.1 2010/10/05    
*    Production release and review comments incorporated.   
*   
* Version 1.0.0 2010/09/20    
*    Production release and review comments incorporated.   
* ---------------------------------------------------------------------------- */

#include "arm_math.h"

/**   
 * @ingroup groupCmplxMath   
 */

/**   
 * @defgroup cmplx_dot_prod Complex Dot Product   
 *   
 * Computes the dot product of two complex vectors.   
 * The vectors are multiplied element-by-element and then summed.   
 *  
 * The <code>pSrcA</code> points to the first complex input vector and   
 * <code>pSrcB</code> points to the second complex input vector.   
 * <code>numSamples</code> specifies the number of complex samples   
 * and the data in each array is stored in an interleaved fashion   
 * (real, imag, real, imag, ...).   
 * Each array has a total of <code>2*numSamples</code> values.   
 *   
 * The underlying algorithm is used:   
 * <pre>   
 * realResult=0;   
 * imagResult=0;   
 * for(n=0; n<numSamples; n++) {   
 *     realResult += pSrcA[(2*n)+0]*pSrcB[(2*n)+0] - pSrcA[(2*n)+1]*pSrcB[(2*n)+1];   
 *     imagResult += pSrcA[(2*n)+0]*pSrcB[(2*n)+1] + pSrcA[(2*n)+1]*pSrcB[(2*n)+0];   
 * }   
 * </pre>   
 *   
 * There are separate functions for floating-point, Q15, and Q31 data types.   
 */

/**   
 * @addtogroup cmplx_dot_prod   
 * @{   
 */

/**   
 * @brief  Floating-point complex dot product   
 * @param  *pSrcA points to the first input vector   
 * @param  *pSrcB points to the second input vector   
 * @param  numSamples number of complex samples in each vector   
 * @param  *realResult real part of the result returned here   
 * @param  *imagResult imaginary part of the result returned here   
 * @return none.   
 */

void arm_cmplx_dot_prod_f32(
  float32_t * pSrcA,
  float32_t * pSrcB,
  uint32_t numSamples,
  float32_t * realResult,
  float32_t * imagResult)
{
  float32_t real_sum = 0.0f, imag_sum = 0.0f;    /* Temporary result storage */

#ifndef ARM_MATH_CM0

  /* Run the below code for Cortex-M4 and Cortex-M3 */
  uint32_t blkCnt;                               /* loop counter */

  /*loop Unrolling */
  blkCnt = numSamples >> 2u;

  /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.   
   ** a second loop below computes the remaining 1 to 3 samples. */
  while(blkCnt > 0u)
  {
    /* CReal = A[0]* B[0] + A[2]* B[2] + A[4]* B[4] + .....+ A[numSamples-2]* B[numSamples-2] */
    real_sum += (*pSrcA++) * (*pSrcB++);
    /* CImag = A[1]* B[1] + A[3]* B[3] + A[5]* B[5] + .....+ A[numSamples-1]* B[numSamples-1] */
    imag_sum += (*pSrcA++) * (*pSrcB++);

    real_sum += (*pSrcA++) * (*pSrcB++);
    imag_sum += (*pSrcA++) * (*pSrcB++);

    real_sum += (*pSrcA++) * (*pSrcB++);
    imag_sum += (*pSrcA++) * (*pSrcB++);

    real_sum += (*pSrcA++) * (*pSrcB++);
    imag_sum += (*pSrcA++) * (*pSrcB++);

    /* Decrement the loop counter */
    blkCnt--;
  }

  /* If the numSamples is not a multiple of 4, compute any remaining output samples here.   
   ** No loop unrolling is used. */
  blkCnt = numSamples % 0x4u;

  while(blkCnt > 0u)
  {
    /* CReal = A[0]* B[0] + A[2]* B[2] + A[4]* B[4] + .....+ A[numSamples-2]* B[numSamples-2] */
    real_sum += (*pSrcA++) * (*pSrcB++);
    /* CImag = A[1]* B[1] + A[3]* B[3] + A[5]* B[5] + .....+ A[numSamples-1]* B[numSamples-1] */
    imag_sum += (*pSrcA++) * (*pSrcB++);


    /* Decrement the loop counter */
    blkCnt--;
  }

#else

  /* Run the below code for Cortex-M0 */

  while(numSamples > 0u)
  {
    /* CReal = A[0]* B[0] + A[2]* B[2] + A[4]* B[4] + .....+ A[numSamples-2]* B[numSamples-2] */
    real_sum += (*pSrcA++) * (*pSrcB++);
    /* CImag = A[1]* B[1] + A[3]* B[3] + A[5]* B[5] + .....+ A[numSamples-1]* B[numSamples-1] */
    imag_sum += (*pSrcA++) * (*pSrcB++);


    /* Decrement the loop counter */
    numSamples--;
  }

#endif /* #ifndef ARM_MATH_CM0 */

  /* Store the real and imaginary results in the destination buffers */
  *realResult = real_sum;
  *imagResult = imag_sum;
}

/**   
 * @} end of cmplx_dot_prod group   
 */